Precision oil heater



Jan. 31, 1950 w. T. FOLEY PRECISION OIL HEATER Filed Nov. so, 1945 m it.

. ILLY/VENTOR. fiflfl'oley, BY v 1 7W.W

l at entecl Jan.

. TED *O FF ICE mixers-MN IIBHEKTER William Fem, Terrace, l larhflhio ApplicatimiNoverizhei's0, 1945 5seriarNovesaoss explains. (01.;32375-8) 1 The resent invention relates to heatirigiap paratus for various purposes ei preersl'cn temperature control-is necessa'1 y' 0 esrrable and has for an obj ect' the provisionbf ap aratus that is -s'afe and economical to operate and that is furtherrr'iore very" compact, and' rel'atively inexpensive of construction.

- Another object 1 of 'the 1 invention de ta provide atmospheric pressure oil heater having ethe' aforementioned advantages and;- wl nch -ls f'r'e'e ofthe hazards of knowii"-oi1="heaters.' I

-"Sti .1l'-'another ohject' of the invention I utility and adapted to exceptional nicety oftem perature control. v

These and other objects are attainewby th' means described herein and exemplified l n -the accompanying'drawings;*in-whieh: I N

Fig. 1- is-a somewhat' schematic"elevational' view of appar'atus embodying the invention, 'o'pe'ra-- ti-v'ely connected with a pressingmachine; parts being broken away. I I a B "Fig. 2* is a"cross sectiorial view' taken on""1lne'= 2 -2 of'Figjl.

advantagesover" water, airof steam" as a-ci r cul'ating heat exchange medium"but""the"' adeption thereof to precision?heating5'equip1fieiifi'has been very limited because ofthereiqliirement for expensive" high pressure" apparatus'ari'd because the use er heretorore kno'wrr oir'neater 'deviees.

*By the means" of 'thepre's'ent fihvefitforf r have feijlnd' that tranquil and safe operatiomof'arffolf pher'ic conditions and thatthe contrb temperature is more nearly" coristantithan tee previously been attained. Thus'fi amenamea re utilize all of'the' advantages'cf qirheam gg apparatus with any" readily" cont/fl11191519 k'itld bf tatiens attending"various'heating apparatus nowj commonly employed. 7

rln adapting the invention to an" oil' heater apparatus I have =-found that moisture in thezoil which LO is' at a-rea whi'oh I have found to be-the top-surface of th heated -oil. Incidentally the moisture initi-eill;

present in" the motor -oil' that 'forms the cir'cwating=heatingmedium and an-y'other mois-' turewhich mayotherwise'--occnr in' -the -mediu'rn lines -allmved to separate from the oil as vapei whem the 611 reaehes-a-temperature of 2 1:12 F;- or higher,and isautomatically trapped,

c'o"de 'd ari'd'removed frem- -the-critical zone h heating-is thus-carriedon= with great As -a r'es ult the'-heat-=contrb1 by inexpensrve ---t'-hermostatic apparatus "is exceed ingl y respons'wa and where it is desired the -reqizired-"-ternperature is maintained constantly Fser-poSsibly a'lesser (variation 'from A emperatureat which a sy'stem embodyin th invention isset:

Phe ensuing description sets forth the invention in connection with a "simplepressingimachine -by-- way-of readily understandable example and riot of limitation; and it will be understood b-y 'tho'se versed in the art'jthat variousmodificatiens will" be dtilizedwithin "the scope of this invention"-in-adaptingthe same in workmanlike manner 'f'or use in j'dirfereht'" kinds and sizesfblt t precision heating systems'for awide varietyof purposes. I

In its i-geheral a$ ects the invention consists m fprov-idingan oil'he'a'te'r'ftank or chamber with any snitablefiring"' mechanism that is subject 8 toreadyorautomatic" control; venting 'the'cil tank orcham-ber to theatmosphere; providing a vapor trap Within" the tank abovethe level or 'the on therein; andmnmping the' heated oil at low pressurWt-hmuglf ahotsupplyline and a; return line ent'to 'an'd fro-nrthe heat utilizin machine, instrumentmr apparatus" of whatever "description.

-In-the drawings a" simple compact "oil" heater its-sidewalls l and"? formed of an integral metal :1 sheet=-to vgrli'iclr" suitable" mounting brackets or say 550" F.

Il'he top level of the oil l'3"is"1ocat'edfat,a'ldistan'ce helowithe"top wall I4 of the tank, which 5 A wall may' comprise a "flanged" sheet j 'of metal by integral flanged wall sections I6 which in this case are welded to the exterior face of back wall l'2. Gas firing tubes ll traverse the tank near the bottom and extend through front wall II and rear wall l2 and open into the lower portion of chest l5 at a distance below a transverse baille E8 in said chest. Entered into the front ends of the firing tubes I! are gas burners l9, desirably of Bunsen type, which are supplied with gas from gas line 20 under the control of an electric gas valve 2! of suitable description, for example as shown in United States Patent No. 1,678,202. Flame and hot products of combustion [pass through the firing tubes I! into the lower flue chest compartment I80 below the baflie Hi from whence they pass through a plurality of heater fiue tubes 22 which extend from the upper portion of compartment I80, through the body of oil It forwardly into the lower part of a compartment 23 on the front wall ll of the tank. From the upper part of compartment 23 an upper series of heater flue tubes 2 extend rearwardly through the oil l3 and communicate with the flue chest H5 in the upper compartment 25 thereof which has a stack pipe connection 26 at or near its top. The total heat exchange surface of tubes ll, 22, and 2d exposed on the inner side to fiame and hot products of combustion and on the outer side to the oil affords a rapid and efficient heat transfer, the speed of which is in any event at least twice as fast as that of any of the other media such as water or air heretofore used. It is noteworthy that this exceptional capacity of motor oil to quickly take up and yield up large amounts of heat with great speed has been the sole justification for its use in the heretofore known dangerous high pressure systems.

It should now be noted that the following simple vapor trap and vent arranged in the top interior of tank 5 above the oil it effectively prevents the heretofore mentioned wild foaming of the oil and by so doing affords a previously unknown degree of accurate heat control using very simple thermostatic devices if desired for the purpose.

I provide a vent pipe 27 in the central part of the top wall [4 of the tank so that moisture in the oil l3 may vaporize and'freely separate from the oil as vapor andrise to said vent 21 wherein it may condense and drop. Suspended from the inner or bottom face of top wall It and below the vent 21' by means of brackets 28 is a large shallow drip bafiie 29 formed like a hollow inverted pyramid with its edges spaced from the inner side wall and top wall of the tank to leave ample flow space around it through which the hot moisture vapors may flow to vent 21. The vent 2? serves as a condenser which directs the condensate into the drip baflie 29 from whence it flows through a drain pipe 39 to the exterior of the tank. I have found that the violent foaming of heated oil has been caused by relatively cold condensate falling on the top surface of the hot oil and that the ability to maintain a temperaturev constant or in other words precision temperature control is practically lost under conditions of heavy foaming.

I therefore am able to employ the simplest types of thermostatic controls and obtain there-- from surprisingly accurate and almost uniform selected temperatures at the point of use.

In the device of Fig. l, for example I heat the pressor head of a pressing machine 3| using a hot oil supply line 32 which is fed with oil at a 4 suitable rate and at low pressure from an electrically driven pump 33 which in this case is turned on and shut off by means of a manually operable switch 34 in known manner. The return fiow'is by way of pipe 35 which leads from the discharge side of machine 3| to tank 5 in the vicinity of firing tubes ll.

The automatic gas firing equipment including burners is with pilot lighters or other igniters (not detailed) and the electrically actuated gas flow valve 2 I maybe of any suitable designs such as are commonly found in the open markets.

'The electrically actuated gas valve 21, a high limit safety thermostat 36 and an adjustable tank temperature thermostat 37 are connected in seriesin an electrical circuit as by wire 38, 39, 40 and .41 in known manner.

Adjustable tank thermostat 3! may be arranged. to, open or close the electrical circuit under temperature changes of 1 F., or more or less depending upon the nicety of control required or needed. This thermostat 3? is desirably located closely adjacent the oil intake end of the pump so that the temperature of oil entering the'pump will be known to be of the temperature for which the thermostat is set $0.5" F. The heat loss in pipe 32 regardless of its length can be accurately calculated or it may be determined empirically. The sum of this heat loss in degrees plus the desired temperature in degrees F. wanted in the machine 3i will be the amount for which thermostat 3? is set. The high limit thermostat 353 will be set at some higher temperature which is well below the flash point temperature of the oil 13 and operates to automatically de-energize the electric gas valve control and shut ofi the gas supply in the event temperature control thermostat 3? should fail. The general arrangement just described will serve eificiently for such equipment and instruments as laundry machines, pressers, vulcanizers and many types of heating and molding presses etc. A fine degree of temperature control and safe carefree and economical operation are a few of the combined advantages realized.

It will be understood that in automatic space heaters, hot air house heating systems and in kindredfa'pparatus the customary air moving fan andan oil heated radiator may be arranged with safety and convenience in any location with or without air. duct systems. The pump and fan employed in such heating systems would be under separate thermostatic control, as under the control of a room thermostat instead of the manual control of the generally corresponding pump 33 of Fig. 1. A delayed action switch for the fan would sometimes be indicated so the starting of the fan may lag a few seconds after the starting of the pump in known manner. The general practices 0'1" the heating engineer for meeting various problems are now well established and widely understood. In adapting the precision oil heaters of the present. invention those practices are simplified in obvious manner because of the compactness and ready adaptability of the devices. The necessity for skilled supervision, inspection and licensed operators is obviated since the hazards and dangers involved are not greater than those attending the wellknown corresponding fired domestic house heating equipment. The devices of the invention may be fired by means of oil burners or coal stokers or other readily controlled firing apparatus, the mode of adapting any of thesebeing obviously quite similar to the herein described gas firing mechanism.

What is claimed is:

1. An atmospheric pressure precision oil heater system comprising the combination with an instrumentality to be heated, of an oil heater tank vented at its top to the atmosphere, a body of high flash point motor oil in the tank, a condensation baiTle in the tank above the oil level and beneath the vent in the top thereof, means to drain the baffle to the exterior of the tank, means to heat the oil below the top surface thereof, thermostatically responsive means extending into the oil and controlling the heating means, a low pressure pump having its intake adjacent said thermostatically responsive member and adapted for circulating the oil at selected rate to a heat utilizing means and a return flow pipe connected to the tank below the pump intake and adapted for connection with the heat utilizing means.

2. An atmospheric pressure precision oil heating apparatus comprising an oil tank having a vent pipe at the top, a drip baflie spacedly mounted within the tank beneath the vent pipe, a body of high flash point motor oil in said tank and having its top surface level below said bafile, a drain tube connecting said bafiie with the exterior of the tank, firing means including flue heater tubes traversing the body of motor oil in the tank, electrical means for controlling said firing means, thermostatically responsive electric switching means arranged and adapted in electrical series with said electrical firing control means to control said firing means in accordance with the temperature of said oil at a predetermined level in the tank, and an oil circulating pipe system including an independently controlled low pressure pump, said pump having its intake disposed closely adjacent the said thermostatically responsive means in the tank.

3. An atmospheric pressure oil heater device comprising an oil tank, a body of high flash point motor oil partially filling the tank and adapted for circulation from said tank and return thereto as a heating medium, means to heat oil in the tank, a vent pipe in the top of the oil tank lead- 7 ing unrestrictedly to atmosphere, a drip bafile beneath the vent and traversing a portion of the interior of the tank above the oil level and draining exteriorly of the tank, and means including oil supply and return pipes and a low pressure pump whereby heated oil may be circulated to and from apparatus to be heated.

4. In an oil heating apparatus the combination of av tank having at its top a vent for the exit of vapors to atmosphere, a drip baffle spaced from the top of the tank directly beneath the vent and having its edges spaced from the inside faces of thesidewalls of the tank, a drain tube connecting the said drip baifie with the exterior of the tank, a body 01 high flash point motor oil in the tank extending to a predetermined level below said baffle, a firing device for heating the oil in the tank to selected temperature, a thermostatically responsive member extending into the body of oil arranged and adapted to control the firing device and means including a low pressure pump connected to the tank for establishing a hot oil flow circuit to and from a device to be heated.

5. Oil heating apparatus comprising a tank having high flash point motor oil partially filling it, firing apparatus to heat the oil in the tank to selected temperature, a thermostatically responsive member extending into the body of oil arranged and adapted to control operation of the firing apparatus, means including a low pressure pump having its intake disposed adjacent the thermostatically responsive member and oil flow pipes for moving heated oil from the tank to a remote device to be heated and return and means to preclude foaming of the oil in the tank including a vent in the top of the tank for removing moisture vapors to atmosphere and a drip baffle beneath said vent and having a drain to the exterior of the tank.

6. In an atmospheric pressure precision heating system the combination of an oil tank, high flash point motor oil partially filling the tank, means for venting moisture vapors liberated from said oil unimpededly to atmosphere and for diverting incidental condensate therefrom exteriorly of the tank, an adjustable thermostat responsive to the temperature of said oil at a predetermined level therein, firing means for heating said oil and operable under the control of said thermostat and means including a pump for selectively circulating the oil at substantially constant temperature from said tank to a utilizing apparatus and back to said tank.

7. An atmospheric pressure precision heater apparatus comprising a tank havin a pipe in the top venting to atmosphere, a drip baffle in the tank beneath the vent pipe and spaced from the interior of the tank, a body of high flash point motor oil in said tank and having its top surface level below said baflle, a drain tube connecting the baflie with the exterior of the tank, heating means traversing the body of oil in the tank, a thermostatically responsive element extending into said body of oil in said tank at a predetermined level arranged and adapted to control the heating means, and an oil circulating pipe system including an independently controlled low pressure pump having its inlet disposed above and closely adjacent said thermostatically responsive element, the system having a return flow connection with the tank below said thermostatically responsive element.

8. An atmospheric pressure heater apparatus comprising a tank, a body of high flash point motor oil partially filling it, a vent pipe leading unobstructedly to atmosphere from the top of the tank, means including a low pressure pump having its intake intermediate the top and bottom of said body of oil for circulating heated oil from the tank to a heat utilizing device and return, and means to preclude foaming of the oil in the tank including a drip baflie interiorly of the tank beneath said vent and arranged to drain exteriorly of the tank.

WILLIAM T. FOLEY.

REFERENCES CITED The following references file of this patent:

UNITED STATES PATENTS are of record in the 

